Power distribution system

ABSTRACT

Disclosed is a power distribution system, comprising a power feed line configured to supply electric power of a given power feed line voltage, a plurality of solid state power control modules connected to the power feed line; each of the solid state power control modules comprising at least one solid state power controller connected to at least one load to be supplied with power from the power feed line and configured to selectively connect the respective load to the power feed line or to disconnect the respective load from the power feed line; the power feed line comprising at least one power feed line segment connecting two adjacent solid state power control modules; wherein the at least two adjacent solid state power control modules are connected by a further electric line connected in parallel to the at least one power feed line segment.

FOREIGN PRIORITY

This application claims priority to European Patent Application No.18160883.7 filed Mar. 9, 2018, the entire contents of which isincorporated herein by reference.

BACKGROUND

Embodiments of the invention relate to a power distribution system, andmore particularly to a power distribution architecture for distributingpower to various electric loads in a vehicle, e.g. in an aircraft. Evenmore particularly, embodiments of the invention relate to fault currentdetection in such power distribution systems, in particular in powerdistribution systems having a ring architecture.

Typically, in a vehicle like an aircraft loads need to be supplied bydifferent voltage levels or type of voltages. Every individual loadrequires its own power supply to convert the feeder voltage supplied bya power source in the vehicle to the necessary voltage level or voltagetype. In combination with solid state power converters (SSPCs) switchingpower to these loads, a plurality of solid state power control modulesare used to switch the feeder voltage to the loads as needed. Each solidstate power control module comprises a plurality of SSPCs connected inparallel to the power feed line with each SSPC having an interface forconnecting to the respective load. The plurality of solid state powercontrol modules is fed by a same power source via the power feed line.For example, the solid state power control modules may be connected in aring architecture in which each of the solid state power control modulesforms a power feed line node and each two adjacent power feed line nodesare connected via a respective power feed line segment. The power feedline segments thus form a ring like structure which is connected to thepower source at a power feed node (which may be formed by one of thesolid state power control modules or may be a specific power feed node).

A problem with such configurations is detection of faults, particularlyground faults, in the power feed line segments. In case a ground faultoccurs in one of the power feed line segments, the two power feed linenodes connected by the respective power feed line segment need to switchoff that power feed line segment. This switching off has to be effectedvery fast. Classical communication between power feed line nodes, as isrealized e.g. via a field bus system like CAN, has turned out too slowfor effecting fast enough switching off of the respective two adjacentpower feed line nodes in case of a fault in the respective power feedline segment.

It would be beneficial to provide a more efficient power distributionsystem being capable of fast switching off of adjacent power feed linenodes in case a fault occurs in one of the feeder line segments.

SUMMARY

Embodiments of the invention provide a power distribution system,comprising a power feed line configured to supply electric power of agiven power feed line voltage, a plurality of solid state power controlmodules connected to the power feed line; each of the solid state powercontrol modules comprising at least one solid state power controllerconnected to at least one load to be supplied with power from the powerfeed line and configured to selectively connect the respective load tothe power feed line or to disconnect the respective load from the powerfeed line; the power feed line comprising at least one power feed linesegment connecting two adjacent solid state power control modules;wherein the at least two adjacent solid state power control modules areconnected by a further electric line connected in parallel to the atleast one power feed line segment.

In particular, the power distribution system may be configured formanaging and distributing electric power in an aircraft. Embodimentsalso provide an aircraft comprising the power distribution system.

Particular embodiments may include any of the following optionalfeatures, alone or in combination with other features:

Each two adjacent solid state power control modules may be connected bya respective power feed line segment and a respective further electricline may be connected in parallel to the respective power feed linesegment.

The power distribution system may have a ring architecture formed by aplurality of solid state power control modules connected in series byrespective power feed line segments, the power feed line segmentsforming a ring configuration.

The further electric line may be a simple wire connection. Thus, noparticular bus system or communication protocol is needed. Informationmay be communicated by a change of voltage level on the wire connection,for example. This way of exchanging information is extremely simple, yetrobust and extremely fast. In further embodiments, such communicationmay be realized by using twisted pair wires or a single wire as thefurther electric line.

Each of the two adjacent solid state power control modules connected bythe at least one power feed line segment may comprise a currentmeasurement unit configured for measuring a load current in the at leastone power feed line segment. In particular, the current measurement unitmay be configured for measuring a load current in the at least one powerfeed line segment or power feed line segments connecting the respectivesolid state power control module with its adjacent solid state powercontrol module or its adjacent solid state power control modules.

Each of the two adjacent solid state power control modules connected bythe at least one power feed line segment may comprise at least onevoltage divider circuit connected to the respective further electricline. Further, each of the two adjacent solid state power controlmodules connected by the at least one power feed line segment maycomprise a first voltage divider circuit connected to the furtherelectric line at a first side thereof, and a second voltage dividercircuit connected to another further electric line at a second sidethereof. Particularly, each voltage divider circuit may comprise a firstresistor and a second resistor connected in series in between a firstdefined DC voltage and a second defined DC voltage or ground, thefurther electric line connected in between the first and secondresistors.

Particularly, the first and second resistors may have a same resistance.

Each voltage divider circuit may comprise a first switch connected inbetween the first DC voltage and the further electric line, and a secondswitch connected in between the further electric line and the second DCvoltage or ground. Particularly, the first and second switches may beoperated according to a direction of current in the at least one powerfeed line segment connecting the respective solid state power controlmodule with the adjacent solid state power control module. For example,the first switch may be closed and the second switch may be open in casethe direction of current in the at least one power feed line segment isfrom the solid state power control module towards the adjacent solidstate power control module. Further, the first switch may be open andthe second switch may be closed in case the direction of current in theat least one power feed line segment is from the adjacent solid statepower control module towards the solid state power control module.

Each of the two adjacent solid state power control modules connected bythe at least one power feed line segment may further comprise at leastone comparator circuit assigned to the voltage divider circuit, thecomparator circuit having an input connected in between the first andsecond resistors of the voltage divider circuit.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter which is regarded as the invention is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe invention are apparent from the following detailed description takenin conjunction with the accompanying drawings in which:

FIG. 1 illustrates a simplified block diagram of a ring powerdistribution architecture according to one embodiment; and

FIG. 2 illustrates a simplified block diagram of two adjacent solidstate power control modules connected by a power feed line segmentaccording to an embodiment.

DETAILED DESCRIPTION

Embodiments described herein relate to a power distribution system,generally indicated by 10 in FIGS. 1 and 2. The power distributionsystem 10 includes a power feed line 12 connected to a power source 13,loads (generally indicated at 14 in FIG. 1) and solid state powercontrol modules 16_1 to 16_6. As indicated schematically only for one ofthe solid state power control modules 16_6 in FIG. 1, each solid statepower control module 16_1 to 16_6 comprises a plurality of solid statepower controllers (SSPCs) connected in parallel to the power feed line12 with each SSPC having an interface for connecting to the respectiveload 14 (see the respective lines IL1 to ILn indicated in FIG. 1). Theplurality of solid state power control modules 16_1 to 16_6 is fed by asame power source 13 via the power feed line 12. The power feed line 12comprises a main power feed line segment IS connected via a power feednode 15 to a ring structure formed by power feed line segments 11 to 17.In the example shown in FIG. 1, the solid state power control modules16_1 to 16_6 are connected in a ring architecture in which each of thesolid state power control modules 16_1 to 16_6 forms a power feed linenode (referred to as SSPC Nodes N1 to N6 in FIG. 1) and the solid statepower control modules of each two adjacent power feed line nodes (inFIGS. 1: 16_1 and 16_2; 16_2 and 15; 15 and 16_3; 16_3 and 16_4; 16_4and 16_5; 16_5 and 16_6; 16_6 and 16_1) are connected via a respectiveone of the power feed line segments 12; 13; 14; 15; 16; 17; 11. Thepower feed line segments 12; 13; 14; 15; 16; 17; 11 thus form a ringlike structure which is connected to the power source 13 at the specificpower feed node 15. Alternatively, the ring structure formed by thepower feed line segments 12, 13, 14, 15, 16, 17, 11 may be connected tothe power source 13 via one of the solid state power control modules16_1, 16_2, 16_3, 16_4, 16_5, 16_6.

SSPCs are used in power management and distribution systems to replacetraditional electromechanical circuit breakers. The main function of anSSPC is to distribute power and to protect various electrical loads. Incomparison to electromechanical devices, SSPCs provide a relatively fastresponse time, and may eliminate arcing during turn-off transient andbouncing during turn-on transient. SSPCs facilitate advanced protectionand diagnostics, allowing for efficient power management anddistribution architectures. SSPCs include power semiconductor devicesthat control power (voltage and/or current) supplied to a load. SSPCsperform supervisory and diagnostic functions in order to identify andprevent overload and short circuit conditions. Components of SSPCs mayinclude power semiconductor switching devices, sensors to monitor outputvoltage and current and power semiconductor device temperature, andcontrol circuitry. The control circuitry may include a microcontrollerconsisting of an arithmetic logic unit (ALU), memory, timer/counters,serial port, input/output (I/O) ports, and clock oscillator. Some SSPCsare programmable by a computer, user or by any proprietary method.

FIGS. 1 and 2 both show a power distribution system 10 comprising apower feed line 12 (including main power feed line segment IS and thepower feed line segments I1, I2, I3, I4, I5, I6, I7 forming the ringlike structure) configured to supply electric power of a given powerfeed line voltage and a plurality of loads 14 to be supplied with powerfrom the power feed line 12. Each of the loads requires power of acharacteristic load voltage. The plurality of solid state power controlmodules 16_1 to 16_6 is connected between the power feed line 12 and theplurality of loads 14. Each of the solid state power control modules16_1-16_6 is configured to selectively connect a respective load of theplurality of loads 14 to the power feed line 12 or to disconnect therespective load of the plurality of loads 14 from the power feed line12. Each of the solid state power control modules 16_1 to 16_6 of thepower distribution system further may comprise at least one powerconversion module (not shown) configured to convert electric power fromthe power feed line voltage to a specific load voltage required by atleast one of the loads 14. The at least one power conversion module isconnected in between the power feed line 12 and the solid state powercontrollers of the respective solid state power control module 16_1-16_6assigned to loads requiring the specific load voltage.

In the power distribution system 10 power received at each load 14 isadjusted by turning on and off SSPCs of the respective solid state powercontrol module 16_1 to 16_6 connected in between the load 14 and thepower feed line 12. By controlling the SSPCs that are turned on and off,the power distribution system 10 can isolate inactive loads or faultyloads of the plurality of loads 14 from the power feed line 12, whilecontinuing to provide power to functional loads of the plurality ofloads 14. The basic concept of this power distribution system 10 is thatan incoming feeder voltage is received by the respective solid statepower control module 16_1 to 16_6. The feeder voltage may be any voltageas typically used in the art. In particular, the feeder voltage may beany type of DC voltage, and may have any voltage level. In aircraftpower distribution systems, typical feeder DC voltages include 28 V DCor 270 V DC. The power distribution system 10 is particularly configuredfor managing and distributing voltages of such voltage type and voltagelevel. One aspect of the power distribution system may be that withinany of the solid state power control modules 16_1 to 16_6, the feedervoltage 12 gets converted to the voltage types and voltage levels neededfor the various loads 14. Efficient DC/DC converters and/or DC/ACconverters may be provided for carrying out such conversion.

An advantage of the ring architecture shown in FIG. 1 is that even incase a ground fault occurs in one of the power feed line segments 11 to17 forming the ring structure (for example, in FIG. 1, a ground fault isindicated at 18 in the power feed line segment 11 connecting the solidstate power control module 16_1 (SSPC Node N1) and the solid state powercontrol module 16_6 (SSPC Node N6)), all solid state power controlmodules 16_1 to 16_6 can still be supplied with electric power frompower source 13. However, it is required that the faulty power feed linesegment in which the ground fault occurred (in FIG. 1: power feed linesegment 11) is switched off. This switching off has to be realized bythe solid state power control modules 16_1 and 16_6 forming the adjacentSSPC Nodes N1 and N6 with respect to the power feed line segment 11,respectively.

In order to control switching off of the respective pair of SSPC NodesN1 to N6, 15 adjacent to a power feed line segment in case of a groundfault event, fast communication between the SSPC Nodes N1 to N6, 15 isprovided. SSPC Nodes N1 to N6, 15 communicate via a field bus system,e.g. a CAN bus system (not shown in FIGS. 1 and 2). However,communication over this field bus system is considered not fast enoughto allow timely switching off of the respective pair of Nodes N1 to N6,15 in case of a ground fault 18. In the embodiment shown in FIGS. 1 and2, the solid state power control modules 16_1 to 16_6 forming SSPC NodesN1 to N6, and node 15, which form the ring structure, are pairwiseconnected by respective power feed line segments 11 to 17, i.e. each twoadjacent SSPC Nodes N1 to N6 or solid state power control modules 16_1to 16_6, and node 15 are connected by a respective power feed linesegment 11 to 17, and are also connected via a further electric line20_1 to 20_7. The further electric line 20_1 to 20_7 is connected inparallel to the respective power feed line segment I1 to I7 in betweenthe corresponding nodes of the ring structure. The further electric line20_1 to 20_7 may be formed by a single wire. Alternatively, the furtherelectric line 20_1 to 20_7 may have a more complicated configuration,e.g. a twisted wire or a coaxial wire.

The further electric lines 20_1 to 20_7 provide a very fastcommunication of a ground fault in one of the power feed line segments11 to 17 to the corresponding pair of adjacent SSPC Nodes N1 to N6, ornode 15, based on the following principle:

A predetermined DC voltage is applied to each of the further electriclines 20_1 to 20_7 in normal operation. For each of the power feed linesegments 11 to 17 forming the ring structure, this voltage can becontrolled by the respective solid state power control modules 16_1 to16_6, 15 forming the corresponding pair of adjacent nodes in the ringstructure. A ground fault occurring in one of the power feed linesegments 11 to 17 (e.g. the ground fault in power feed line segment 11indicated at 18 in FIG. 1) will cause a change in the voltage level ofthe corresponding further electric line 20_1 to 20_7 (e.g. in thevoltage level of the further electric line 20_1 in FIG. 1). This changein voltage level of the corresponding further electric line 20_1 to 20_7can be detected by the respective adjacent solid state power controlmodules 16_1 to 16_7, 15 very fast. In response to such detection thesolid state power control modules 16_1 to 16_6 may switch off thecorresponding power feed line segment 11 to I7. This solution is veryfast compared to classical communication, particularly much faster thannormal serial bus communication using field bus systems like CAN. As aconsequence of the fast switching off of the faulty power feed linesegment 11 to 17 by its adjacent nodes (solid state power controlmodules) in the ring structure, other nodes of the ring structure, whichin principle would also see the fault, are less subject to stress. It ispossible to operate the power distribution system 10 in a ring structurewithout opening any of the power feed line segments 11 to 17 on purposeduring normal operation to safely detect a fault. This saves timedisconnecting the fault from the power distribution system. The circuitis small and robust.

Detection of a change of the voltage level on the further electric line20_1 to 20_7 is based on the following principle: During normaloperation, the load current I_load on the respective power feed linesegment 11 to 17 connecting two adjacent SSPC Nodes N1 to N6, 15 flowsfrom the one SSPC Node (e.g. from SSPC Node N1 or solid state powercontrol module 16_1 in FIGS. 1 and 2) to the other SSPC Node (e.g. toSSPC Node N6 or solid state power control module 16_6 in FIGS. 1 and 2).Therefore, the direction of load current I_load detected by load currentmeasurement units 22_1 to 22_6 of the respective adjacent SSPC Nodes(e.g. by load current measurement unit 22_1 of SSPC Node N1 and loadcurrent measurement unit 22_6 of SSPC Node N6 in FIGS. 1 and 2) is thesame.

FIG. 1 indicates that a ground fault occurs in one of the power feedline segments 11 to 17 between two adjacent SSPC Nodes, namely in powerfeed line segment 11 at the location designated by 18. Power feed linesegment 11 connects SSPC Node N1 (formed by solid state power controlmodule 16_1) with SSPC Node N6 (formed by solid state power controlmodule 16_6). As shown by the two arrows in FIG. 1, in case of groundfault 18, the load current I_load on the respective power line segment11 connecting both SSPC Nodes N1 and N6, as detected by load currentmeasurement unit 22_1 of SSPC Node N1 and load current measurement unit22_6 of SSPC Node N6, respectively, no longer flows in a same direction.Rather, the load current I_load flows in a direction away from each ofthe SSPC Nodes N1, N6 towards the location of the ground fault 18 in thecorresponding power line segment 11. E.g. in FIG. 1 the load currentI_load detected by the first load current measurement unit 22_1 willflow from SSPC Node N1 (formed by solid state power control module 16_1)to the right towards the location of the ground fault 18. At the sametime the load current I_load detected by the sixth load currentmeasurement unit 22_6 will also flow away from the SSPC Node N6 (formedby solid state power control module 16_6) to the left towards thelocation of the ground fault 18.

This change in direction of the load current I_load when detected at thetwo adjacent SSPC Nodes N1, N6, respectively, may be used to cause achange in voltage level of the further electric line 20_1 connecting therespective SSPC Nodes N1 and N6 (in parallel to the power feed linesegment 11 connecting the respective SSPC Nodes N1 and N6). Hence, it ispossible to detect occurrence of the ground fault and also the locationof the ground fault.

For example, detection of the ground fault 18 may be based on thefollowing principle, using the circuit shown in FIG. 2. FIG. 2 shows thesituation indicated in FIG. 1 with power feed line segment 11 connectingSSPC Node N1 (formed by the first solid state power control module 16_1)with SSPC Node N6 (formed by the sixth solid state power control module16_6). SSPC Node N1 (formed by the first solid state power controlmodule 16_1) includes first load current measurement unit 22_1 fordetecting the direction of load current I_load in SSPC Node N1. SSPCNode N6 (formed by the sixth solid state power control module 16_6)includes a sixth load current measurement unit 22_6 for detecting thedirection of load current I_load in SSPC Node N6. In addition to powerfeed line segment I1, SSPC Node N1 and SSPC Node N6 are also connectedby a further electric line 20_1. Further electric line 20_1 is connectedin parallel to power feed line segment 11.

As shown in FIG. 2 each of the two adjacent SSPC Nodes N1 (formed by thefirst solid state power control module 16_1) and N6 (formed by the sixthsolid state power control module 16_6) connected by the at least onepower feed line segment 11 comprises at least one voltage dividercircuit 24_1, 24_6 connected to the respective further electric line20_1.

FIG. 2 further shows that each of the two adjacent SSPC Nodes N1 (formedby the first solid state power control module 16_1) and N6 (formed bythe sixth solid state power control module 16_6) also comprises a secondvoltage divider circuit 26_1, 26_6 connected to another further electricline 20_2, 20_7 at a second side thereof.

Each voltage divider circuit 24_1, 24_6 comprises a first resistor 28and a second resistor 30 connected in series in between a firstpredefined DC voltage 36 and a second predefined DC voltage or ground38. The further electric line 20_1 is connected in between the firstresistor 28 and the second resistor 30 of the voltage divider circuits24_1 and 24_6. In the embodiment shown the first and second resistors 28and 30 have a same resistance. Other resistance values may be selectedfor the first and second resistors, if desired.

Each voltage divider circuit 24_1 and 24_6 further comprises a firstswitch 32 connected in between the first DC voltage 36 and the furtherelectric line 20_1. Moreover, each voltage divider circuit 24_1 and 24_6further comprises a second switch 34 connected in between the furtherelectric line 20_1 and the second DC voltage or ground 38.

The first and second switches 32, 34 of the solid state power controlmodule 16_1 are operated according to a direction of load current I_loaddetected by the respective first load current measurement unit 22_1 inthe at least one power feed line segment 11 connecting the first solidstate power control module 16_1 with the adjacent sixth solid statepower control module 16_6. The first and second switches 32, 34 of thesixth solid state power control module 16_6 are operated according to adirection of load current I_load detected by the respective sixth loadcurrent measurement unit 22_6 in the at least one power feed linesegment 11 connecting the sixth solid state power control module 16_6with the adjacent first solid state power control module 16_1.

The following rule applies: The first switch 32 of the first solid statepower control module 16_1 is closed and the second switch of the firstsolid state power control module 16_1 is open in case the direction ofload current I_load detected by the first load current measurement unit22_1 in the at least one power feed line segment 11 is from the firstsolid state power control module 16_1 towards the adjacent sixth solidstate power control module 16_6 (load current flows in outwarddirection). Correspondingly, the first switch 32 of the sixth solidstate power control module 16_6 is closed and the second switch of thesixth solid state power control module 16_6 is open in case thedirection of load current I_load detected by the sixth load currentmeasurement unit 22_6 in the at least one power feed line segment 11 isfrom the sixth solid state power control module 16_6 towards theadjacent first solid state power control module 16_1 (load current flowsin outward direction).

The first switch 32 of the first solid state power control module 16_1is open and the second switch 34 of the first solid state power controlmodule 16_1 is closed in case the direction of load current I_loaddetected by the first load current measurement unit 22_1 in the at leastone power feed line segment 11 is from the adjacent sixth solid statepower control module 16_6 towards the first solid state power controlmodule 16_1 (load current flows in inward direction). The first switch32 of the sixth solid state power control module 16_6 is open and thesecond switch 34 of the sixth solid state power control module 16_6 isclosed in case the direction of load current I_load detected by thesixth load current measurement unit 22_6 in the at least one power feedline segment 11 is from the adjacent first solid state power controlmodule 16_1 towards the sixth solid state power control module 16_6(load current flows in inward direction).

Therefore, in normal operation (i.e. in the absence of a ground fault onthe power feed line segment 11) load current will flow in outwarddirection at the first solid state power control module 16_1, andtherefore the first switch 32 of the first solid state power controlmodule 16_1 will be closed and the second switch 34 of the first solidstate power control module 16_1 will be open. In contrast, in normaloperation (i.e. in the absence of a ground fault on the power feed linesegment 11) load current will flow in inward direction at the sixthsolid state power control module 16_6, and therefore the first switch 32of the sixth solid state power control module 16_6 will be open and thesecond switch 34 of the sixth solid state power control module 16_6 willbe closed. As a result, the voltage level on the further electric line20_1 will be half the difference between the first DC voltage 36 and thesecond voltage or ground 38.

In case of a ground fault on the power feed line segment 11, loadcurrent I_load will flow in outward direction at the first solid statepower control module 16_1, and therefore the first switch 32 of thefirst solid state power control module 16_1 will be closed and thesecond switch 34 of the first solid state power control module 16_1 willbe open. However, in case of a ground fault on the power feed linesegment 11, also load current I_load will flow in outward direction atthe sixth solid state power control module 16_6, and therefore the firstswitch 32 of the sixth solid state power control module 16_6 will beclosed and the second switch 34 of the sixth solid state power controlmodule 16_6 will be open. As a result, the voltage level on the furtherelectric line 20_1 will change (increase in this case) and no longer beequal to half the difference between the first DC voltage 36 and thesecond voltage or ground 38.

Each of the two adjacent solid state power control modules 16_1, 16_6connected by the at least one power feed line segment 11 comprises atleast one comparator circuit 40. The comparator circuit 40 is assignedto the respective voltage divider circuit 24_1, 24_6. The comparatorcircuit 40 has an input connected in between the first and secondresistors 28, 30 of the respective voltage divider circuit 24_1, 24_6.Thus, the input of the comparator circuit 40 is supplied with a voltagecorresponding to the voltage level on the further electric line 20_1. Achange in the voltage level on the further electric line can thus bedetected by comparator 40, and in response to detection of a change involtage level at the comparator input, a switch off operation of thepower feed line segment 11 will be tripped by the comparator.

The first solid state power control module 16_1 also comprises a secondvoltage divider circuit 26_1 at a side opposite to the side of the firstvoltage divider circuit 24_1. The sixth solid state power control module16_6 also comprises a second voltage divider circuit 26_6 at a sideopposite to the side of the first voltage divider circuit 24_6. Thesecond voltage divider circuit 26_1 of the first solid state powercontrol module 16_1 is connected to another further electric line 20_2.The second voltage divider circuit 26_6 of the first solid state powercontrol module 16_6 is connected to another further electric line 20_7.Otherwise the second voltage divider circuits 26_1 and 26_6 have thesame configuration as the first voltage divider circuits 24_1 and 24_6described in detail above. Reference is made to this description whichalso applies with respect to the second voltage divider circuits.

The power management and distribution system 10 is configured formanaging and distributing electric power in an aircraft.

While the invention has been described in detail in connection with onlya limited number of embodiments, it should be readily understood thatthe invention is not limited to such disclosed embodiments. Rather, theinvention can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of theinvention. Additionally, while various embodiments of the invention havebeen described, it is to be understood that aspects of the invention mayinclude only some of the described embodiments. Accordingly, theinvention is not to be seen as limited by the foregoing description, butis only limited by the scope of the appended claims.

1. A power distribution system, comprising a power feed line configured to supply electric power of a given power feed line voltage, a plurality of solid state power control modules connected to the power feed line; each of the solid state power control modules comprising at least one solid state power controller connected to at least one load to be supplied with power from the power feed line and configured to selectively connect the respective load to the power feed line or to disconnect the respective load from the power feed line; the power feed line comprising at least one power feed line segment connecting two adjacent solid state power control modules; wherein the at least two adjacent solid state power control modules are connected by a further electric line connected in parallel to the at least one power feed line segment.
 2. The power distribution system according to claim 1, wherein each two adjacent solid state power control modules are connected by a respective power feed line segment and a respective further electric line is connected in parallel to the respective power feed line segment.
 3. The power distribution system according to claim 1, wherein the power distribution system has a ring architecture formed by a plurality of solid state power control modules connected in series by respective power feed line segments, the power feed line segments forming a ring configuration.
 4. The power distribution system according to claim 3, wherein the further electric line is a wire connection.
 5. The power distribution system according to claim 4, wherein the wire connection is a twisted pair wire or a single wire.
 6. The power distribution system according to claim 1, wherein each of the two adjacent solid state power control modules connected by the at least one power feed line segment comprises a current measurement unit configured for measuring a load current in the at least one power feed line segment.
 7. The power distribution system according to claim 1, wherein each of the two adjacent solid state power control modules connected by the at least one power feed line segment comprises at least one voltage divider circuit connected to the respective further electric line.
 8. The power distribution system according to claim 7, wherein each of the two adjacent solid state power control modules connected by the at least one power feed line segment comprises a first voltage divider circuit connected to the further electric line at a first side thereof, and a second voltage divider circuit connected to another further electric line at a second side thereof.
 9. The power distribution system according to claim 8, wherein each voltage divider circuit comprises a first resistor and a second resistor connected in series in between a first defined DC voltage and a second defined DC voltage or ground, the further electric line connected in between the first and second resistors.
 10. The power distribution system according to claim 9, wherein the first and second resistors have a same resistance.
 11. The power distribution system according to claim 8, wherein each voltage divider circuit comprises a first switch connected in between the first DC voltage and the further electric line, and a second switch connected in between the further electric line and the second DC voltage or ground.
 12. The power distribution system according to claim 11, wherein the first and second switches are operated according to a direction of current in the at least one power feed line segment connecting the respective solid state power control module with the adjacent solid state power control module.
 13. The power distribution system according to claim 12, wherein the first switch is closed and the second switch is open in case the direction of current in the at least one power feed line segment is from the solid state power control module towards the adjacent solid state power control module.
 14. The power distribution system, according to claim 12, wherein the first switch is open and the second switch is closed in case the direction of current in the at least one power feed line segment is from the adjacent solid state power control module towards the solid state power control module.
 15. The power distribution system according to claim 7, wherein each of the two adjacent solid state power control modules connected by the at least one power feed line segment comprises at least one comparator circuit assigned to the voltage divider circuit, the comparator circuit having an input connected in between the first and second resistors of the voltage divider circuit 